Lighting circuit inoperative (in domestic property) but MCB has not tripped out on main board; no work has been done on the circuit or fittings/cabling interfered with

Roger, June 2009

What it sounds like is an open circuit fault.switch off at main switch on mcb distribution board, drop all the covers on ceiling roses and check for loose broken wiring at terminals. its not unheard of for apprentices to do all this work on new installations and they can some times overtighten( or under tighten!) the terminal screws or when stripping the insulation the copper conductor gets nicked and later snaps but remains touching so give all the wires a gentle tug to check they are secure. take your wall switches off and check them for correct termination. wiring sometimes goes back to central jointbox in roof space or underfloor, if youve got one of these you need to locate it and check all connections.
replace all covers and switch power back on. if still no joy you need to check for live and neutral at a ceiling rose near to distribution board but you will need a proper testlamp so may be best to call an electrician at this point

sparkybloke, June 2009

A live or neutral wire may have come adrift from its connection early in the circuit - the MCB may be defective - a wire may be detached in the consumer unit.

I am unable to think of any other probable cause apart from a magic spell having be cast against you.

A mains tester screwdriver at any ceiling rose will help in diagnosis - if there's mains voltage showing you eliminate the Live circuit and the MCB - it's the neutral circuit after that...

Good luck...

Peccavi, June 2009

Insufficient information to diagnose the problem.
Is the circuit fuse live?

geoff in Wales, June 2009